Method for the flotation of oxidic ores with calcareous and dolomitic gangue

ABSTRACT

A method for the flotation of minerals and ores with a calcareous and dolomitic gangue, such as oxidized ores, especially of copper, in which there are incorporated in the flotation pulps, when so required, together with modifying reagents acting on the minerals to be collected, modifying products acting on the gangues, especially on calcareous and dolomitic gangues, the said gangue-modifying products being preferably agents selected from the group comprising the polymers of acrylic acid, their derivatives and their equivalents which are soluble in water.

United States Patent Inventor Appl. No. Filed Patented Assignee Priority Jacques A. DeCuyper Slerrebeek, Belgium Oct. 21, 1969 Mar. 30, 1971 Societe De Produits Chimiques DAuby Neuilly-sur-Seine (Hauts de Seine), France May 1 1, 1966 France Continuation of application Ser. No. 637,621, May 11, 1967, now abandoned.

METHOD FOR THE FLOTATION OF OXIDIC ORES WITH CALCAREOUS AND DOLOMITIC GANGUE 7 Claims, No Drawings US. Cl

[56] References Cited UNITED STATES PATENTS 1,312,668 8/1919 Bacon 209/167X 2,740,522 4/1956 Aimone.... 209/166 2,955,932 10/1960 Goren 210/54X 2,980,609 4/1961 Mouse 210/54 FOREIGN PATENTS 141,827 11/1960 U.S.S.R. 209/167 378,063 7/ 1932 Great Britain 209/167 Primary Examiner-Frank W. Lutter Assistant ExaminerRobert Halper Atl0rneyStevens, Davis, Miller & Mosher equivalents which are soluble in water.

METHOD FOR THE FLOTATION OF OXIDIC ORES WITH CALCAREOUS AND DOLOMllTlC GANGUE This application is a continuation of application Ser. No. 637,621, filed 1967 and now abandoned.

acetone, or certain metallic ions, make it possible to limit the degree of polymerization to a suitable value.

The achievement of a good selectivity is particularly difficult to the case of oxidized ores, especially when these latter in the flotation of minerals, and especially of ores, it is al- 5 are floated by means of collectors such as fatty acids, alcohols ways sought to improved the selectivity of the separation or their derivatives (soaps, sulfonates, sulfates, phosphates, between the minerals which its is desired to recover and those amine salts, etc.) The majority of the common ions (Fe of the gangue. To this end, use is frequently made of reagents Ca, Mg**...) which are practically always present in a flotaknown as modifiers, the effect of which is to cause a segregation pulp, have in fact a tendency to *activate" the minerals of tion of the minerals from the gangue, so as to prevent them l0 the gangue in the presence of these collectors. from floating with the minerals to be collected. Amongst the Furthermore, when the gangue contains dolomite, the latter reagents currently used for this purpose, there must be cited is even liable to be collected in preference to the useful the alkalis such as sodium carbonate, lime and caustic soda, minerals. Thus, in the treatment by flotation of oxidized ores sodium silicate, acids, sodium cyanide and sulfides, etc. of copper, lead and zinc, recourse is frequently had to the These reagents are however not sufficient in very many method of sulfuration which is known per se. case, and especially in the case of oxidized ores and when the In accordance with the invention, this sulfuration is effected gangues are calcareous and dolomitic, the selectivity then by addition to the pulp of ground ore, or reagents such as sodifrequently leaving much to be desired, because the reactions urn hydrosulfide, or sodium, barium or ammonium sulfides. of the rich minerals and those of the minerals of the gangue The oxidized minerals which it is desired to recover in the are not sufficiently differentiated. v foam during the flotation, thus become superficially sul- In order to overcome this difficulty, it is proposed, in acfurized. For this reason, they behave like sulfides, and their cordance with the invention, to incorporate in the flotation separation by flotation is then effected by means of the collecpulps, when so desired at the same time with modifying retor reagents utilized currently in the flotation of sulfurated agents acting on the minerals to be collected, modifying reores. agents acting on the gangues, especially on the calcareous and The application of the method and the products in acdolomitic gangues. cordance with the invention makes it possible to obtain, for As modifying reagents of the gangues, there are preferably the same consumption of collector reagent, a marked increase chosen, in accordance with the invention, agents comprised in in the selectivity of separation, without reducing the rate of the family of the polymers of acrylic acid, of their derivatives T recovery. This latter rate is even frequently increased, the and their equivalents which are soluble in water. The solutions floatability of the useful material being improved due to the of polymers utilized within the framework of the invention fact that its surface is less coated by the sludges of the gangue. have advantageously a mean viscosity (Brookfield) at 25 C. In addition, the method offers the following advantages: comprised between 5 and 500 centipoises (for an aqueous 1. It reduces the content of lime and magnesia in the consolution containing 20 percent of active products), the best centrates, thus improving the metallic content of these latter. results being obtained with solutions having a viscosity com- This results in a reduction of the cost of consumption of acid prised between 5 and l00 centipoises. Higher viscosities, corwhen the concentrated oxide must be subsequently treated by responding to molecular weights in excess of 10,000 have lixiviation. proved to be much less favorable, since they give rise to floc- 2. It improves the flotation of the sludges and increases their culations which adversely affect the process of flotation emrate of recovery. ployed according to the invention. 0 3. The addition of the modifiers proposed according to the The modifying agents according to the invention adinvention does not necessitate any conditioning over a long vantageously correspond to the following general formula {or period and does not have any adverse effect on the stability of the like): the foam.

. 4. The content of the concentrates being increased for the H R samerecover f tlth ht f t t t b fl- I yo mea, eweig oconcenraeso e1 ti'1-C tered is reduced. This results in a reduction of the costs of fil- (300x n tration and of the costs of any possible transport of the concentrates. in which R represents H or CH X represents H or a cation Other characteristics of the invention will become apparent which may be mineral (Na, Li, K, NH etc.) or organic (orfrom the description which follows below of examples of apganic bases giving, with the polymers forming the object of the plication of the invention. The first examples relate to a invention, compounds soluble 'in water), n being a number retreatment of residues of the flotation of the sulfides of a sulwhich is very variable according to the degree of polymerizafurated and oxidized mixed copper ore obtained from the tion, the said degree of polymerization being approximately Katanga. estimatable as a function of the viscosity of the solutions ob- In order to permit comparison to be made, the residues in tained. question were first subjected to a standard sulfuration and These acrylic polymers correspond advantageously to the flotation treatment in a laboratory Denver cell. The consumpcriteria of viscosity specified above, and are preferably obtion of reagents was as follows: tained by polymerization of acrylic acid or methacrylic acid or Sulfurating agent: l.5 kg. of sodium hydrosulfide per ton of of their salts, following the known method making use of ore; REDOX catalysts which contain simultaneously an oxidizing Collector 80 grams of potassium amylxanthate per ton of agent and a reducing agent, e.g. hydrogen peroxide ferrous ore: sulfate or ammonium persulfate sodium bisulfite, etc. The Foaming agents: 190 grams of emulsion of pine oil and gasdosing of the catalyst employed, the regulation of the reaction oil per tone of ore. temperatures and the addition of regulators such as methanol, The results are shown in the following table.

Effic ency Weight Efficiency, CaO+MgO, CaO+MgO, Product percent Cu percent Cu percent percent percent 1515 concentrate 1. 7 25. 8O 23. 8 5. 35 0.6 2nd concentrate. 1. 2 19. 12. 9 6. 21 0. 5 3rd concentrate. 1. 0 17. 65 9. 3 6. 72 0. 4

Total concentratea. 9 21. 46. 0 5. 96 1. 5

These results will be compared with those obtained in three examples of application of the method and products according to the invention, which utilize, as indicated below:

l. A modifying agent A according to the above-specified formula and constituted by an aqueous solution with 20 per- 5 cent of polyacrylic acid having a Brookfield viscosity at 25 C. equal to 40 centipoises.

2. A modifying agent B, similar to the preceding, having a viscosity equal to 50 centipoises.

3. A modifying agent C, having a viscosity equal to 13 cenl tipoises.

In the first example, 250 grams of polymer A were added; in the second, 330 grams of polymer B, and in the third example, 158 grams of polymer C per ton of ore, all the other conditions of the sulfuration treatment being furthermore maintained the same.

ize respectively:

viscosity equal to 6 to 7 centipoises;

example 2, the viscosity of which is 50 centipoises.

These results will be compared with those obtained in the two examples of application and 6 which follow below; of methods and products according to the invention, which util- Example 42: A gangue modifier D constituted by a modifier similar to the preceding modifying agents A, B and C, having a Example 5e: The gangue-modifying agent B of the previous In the two examples 4 and 5, there have been added 780 grams of polymer per ton of ore, all the other conditions of sulfuration treatment being furthennore kept the same.

As clearly shown in all the examples given, the addition of a relatively small quantity of acrylic acid polymer has at all times a good effect on the efficiency and on the content of the The results are shown in the following tables: concentrate.

EXAMPLE 1.POLYMER A Efiiciency Weight Efficiency, CaO-l-MgO, CaO+MgO, Product percent Cu percent Cu percent percent percent 1st concentrate. 2. 4 26.15 33. 3 4. 49 I 0.7 2nd concentrate. 1. 3 17.40 12. 2 6. 23 0. 5 3rd concentrate 0.7 15. 50 6.0 7. 13 0.3

Total concentrate. 4. 4 21.80 51. 5 5. 1. 4

Waste 95. 6 0. 94 48. 5 15. 37 98. 6 Supply 100. 0 1. 85 100. 0 i4. 93 100. 0

EXAMPLE 2.POLYMER B Efficiency Weight Efficiency, CaO-l-MgO, CaO+MgO, Product percent Cu percent Cu percent percent percent 1st concentrate 1.6 29. 40 25. 3 4. 59 0. 5 2nd concentrate... 1.4 20. 25 15. 2 6. 02 0.6 3rd concentrate. 0.8 17. 10 G. 9 6. 92 0.3

Total eonccntrate. 3. 8 23. 47. 4 5. 1. 4

Waste 00. 2 1. 02 52. 0 15. 20 98.6 Supply 100. 0 1. 86 100. 0 14. 83 100. 0

EXAMPLE 3.POLYMER C Efficiency Weight Efficiency, CaO+MgO, CaO+Mg0, Product percent Cu percent Cu percent percent percent 1st concentrate- 1. 7 28. 70 26. 4 4. 34 0. 5 2nd concentrate..." 1. 2 21. 40 14.0 5. 30 0.4 3rd concentrate. 0. 9 17. 90 9. 3 6. 34 0.4

Total eoneentrate. 3. 8 24. 30 49. 7 5. 03 1. 3

Waste 00. 2 0. 96 50. 3 15. 20 98. 7 Supply 100. 0 1.83 100. 0 14. 83 100. 0

A second series of examples (4 and 5) relates to the treat- EXAMPLE 4e.POLYMER D ment of lead-bearing waste, rich n cerusite and having a cal- Weight Pb Emciency' careous gangue which are submitted in known manner to a Product percent percent Pb percent sulfuration treatment. This waste was ground to 85 percent- 1st concentrate n 19 51 12 5&8 200 mesh, in the presence of sodium silicate 100 grams per 2nd eoneeritrate 3. 2 42. 34 10. 2 ton). lt was then treated by sulfuration and flotation in a concentrate 6 30-68 7 laboratory Denver cell. The consumption of reagents was as Total concentrate 12.7 50.12 75.7 follows: Waste 87. 3 2. 34 24. 3 Sulfuration agent: 3.8 kg. of sodium hydrosulfide per ton of Supply 100.0 s. 39 100. 0 ore;

fCollector: 160 grams of amylxanthate of potassium per ton EXAMPLE E o ore;

- Weight Pb Efficiency. Foaming agents. 30 grams of cresylic acid and 20 grams of Product percent percent Pb percent Dowfroth 250 per ton of ore. 1 t t t 9 5 52 12 58 7 5 00110811 ra e- The results are shown in the following table. 2nd Concentrate 5.1 95 5 3rd concentrate. 1. 7 25. 50 5. 3 Weight Pb Efficiency, Product percent percent Pb percent Total concentrate. 16. 3 43. 60 84. 5

1st concentrate 7. 9 52. 02 4s. 5 w te 83.7 1. 56 15.5 2nd concentrate- 5. 3 37. 60 2 8 Supply 100. 0 8. 43 100. 0 3rd concentrate 3. 3 18. 51 7. 3

T talc c trat 1 2 0 on e a 40 6 79 6 It will be understood that the five examples given above are Waste in no wa limitative and that without thereb dc artin from Supply 100.0 s. 42 100. 0 y y p g the scope of the invention, the latter may be applied on the one hand to the treatment of all minerals of any kind having a calcareous and/or dolomitic gangue or the like and, on the other hand, the nature and the proportions of the modifying additives employed either alone or in mixtures may be modified in any suitable manner, in addition to the collector and foaming additives of the flotation process.

Instead of acrylic acid polymers. there could particularly be employed all equivalent products, such as linear anionic polymers. soluble in water, obtained by the hydrolysis of polynitriles, of polyesters or of copolymers having the same adding to said flotation medium at least one modifying agent acting on said gangue selected from the group of water-soluble polymers of acrylic acid corresponding to the general formula:

6 lmi ('10 ox/n wherein R is H or CH, X is H or a cation from the group consisting of Na, Li, K, NH and organic bases imparting water solubility to the polymer, and n is an integer corresponding to the degree of polymerization represented by a Brookfield viscosity of as low as 6 and as high as 50 centipoises at 25 C.

2. Method according to claim 1 which the material being treated is the residue from a primary flotation of a copper ore.

3. Method according to claim'l in which the material being treated is a lead-bearing waste.

4. Method according to claim 1 in which the ore is an oxidized ore.

5 Method according to claim 4 in which the gangue is dolomitic and sulfurating agent is present in the flotation medium.

6. Method according to claim 5 in which the ore is a copper ore.

7. Method according to claim 4 in which the ore is a lead ore and a sulfurating agent is present in the flotation medium. 

2. Method according to claim 1 which the material being treated is the residue from a primary flotation of a copper ore.
 3. Method according to claim 1 in which the material being treated is a lead-bearing waste.
 4. Method according to claim 1 in which the ore is an oxidized ore.
 5. Method according to claim 4 in which the gangue is dolomitic and sulfurating agent is present in the flotation medium.
 6. Method according to claim 5 in which the ore is a copper ore.
 7. Method according to claim 4 in which the ore is a lead ore and a sulfurating agent is present in the flotation medium. 